Effect of radiotherapy after breast-conserving surgery for ductal carcinoma in situ: 20 years follow-up in the randomized SweDCIS Trial.

Abstract

PURPOSE:

Four randomized studies show that adjuvant radiotherapy (RT) lowers the risk of subsequent ipsilateral breast events (IBEs) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) by approximately 50% after 10 to 15 years. We present 20 years of follow-up data for the SweDCIS trial.

PATIENTS AND METHODS:

Between 1987 and 1999 1,046 women were randomly assigned to RT or not after BCS for primary DCIS. Results up to 2005 have been published, and we now add another 7 years of follow-up. All breast cancer events and causes of death were registered.

RESULTS:

There were 129 in situ and 129 invasive IBEs. Absolute risk reduction in the RT arm was 12.0% at 20 years (95% CI, 6.5 to 17.7), with a relative risk reduction of 37.5%. Absolute reduction was 10.0% (95% CI, 6.0 to 14.0) for in situ and 2.0% (95% CI, -3.0 to 7.0) for invasive IBEs. There was a nonstatistically significantly increased number of contralateral events in the RT arm (67 v 48 events; hazard ratio, 1.38; 95% CI, 0.95 to 2.00). Breast cancer-specific death and overall survival were not influenced. Younger women experienced a relatively higher risk of invasive IBE and lower effect of RT. The hazard over time looked different for in situ and invasive IBEs.

CONCLUSION:

Use of adjuvant RT is supported by 20-year follow-up. Modest protection against invasive recurrences and a possible increase in contralateral cancers still call for a need to find groups of patients for whom RT could be avoided or mastectomy with breast reconstruction is indicated.

• Authors: Fredrik Wärnberg, Hans Garmo, Stefan Emdin, Veronica Hedberg, Linda Adwall, Kerstin Sandelin, Anita Ringberg, Per Karlsson, Lars-Gunnar Arnesson, Harald Anderson, Karin Jirström, Lars Holmberg
• Journal: Journal of clinical oncology : official journal of the American Society of Clinical Oncology (J Clin Oncol) Vol. 32 Issue 32 Pg. 3613-8 (Nov 10 2014) ISSN: 1527-7755 [Electronic] United States
• PMID: 25311220 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 by American Society of Clinical Oncology.

Topics

• Adult
• Aged
• Breast Neoplasms (diagnosis, radiotherapy, surgery)
• Carcinoma in Situ (diagnosis, radiotherapy, surgery)
• Combined Modality Therapy
• Female
• Follow-Up Studies
• Humans
• Mammography (methods)
• Mass Screening (methods)
• Mastectomy, Segmental (methods)
• Middle Aged
• Neoplasm Recurrence, Local
• Outcome Assessment, Health Care (statistics & numerical data)
• Proportional Hazards Models
• Radiotherapy, Adjuvant
• Sensitivity and Specificity
• Survival Analysis
• Sweden
• Time Factors